This invention relates to fuel lines for use in fuel injection systems to interconnect a fuel pump and an injection nozzle.
Fuel injection pumps employed in fuel injection systems generate extremely high hydraulic pressures which may range upwardly from several thousand pounds per square inch. The pressures are generated in pulse form to direct fuel from the pump through fuel lines to injection nozzles, typically associated with engines or the like. Because of raid cycling and/or vibration associated with the power plant with which the injection system may be used, there may be a tendency for fittings to loosen and/or conduits to fracture under the pressures involved.
In the case of either, fuel spillage will occur and such spillage is particularly undesirable where the engine is operating in an enclosed area and/or substantially unattended thereby causing combustible vapors to form and/or permitting a sizable accumulation of fuel to occur in an area where it is unlikely to be discovered.
To avoid such difficulties, it has been suggested to provide double walled fuel lines so that if the fuel carrying conduit ruptures, lost fuel will be captured by an outer conduit to prevent leakage. This approach eliminates leakage due to fuel line rupture but does not prevent leakage due to loosening of interengaging parts which are intended to be sealed. Moreover, heretofore, this approach has been practiced using rigid, precisely dimensioned, unbendable pipes or the like, thereby making it extremely difficult to route fuel lines from an injection pump to an injection nozzle.